Vitamin C is an essential nutrient that the body requires for certain functions. However, high amounts of vitamin C may harm a person with kidney damage.

Vitamin C is in certain foods and supplements. The body uses it to help promote healing and to maintain skin, bones, and connective tissue. However, consuming too much vitamin C may be dangerous for a person with a kidney disorder. High levels of vitamin C may increase their risk of developing kidney stones.

The kidneys are two bean-shaped organs located below a person’s rib cage. They filter a person’s blood to remove waste and excess water, which becomes urine. Urine then flows to the bladder, where the body passes the waste fluid during urination.

Read on to learn more about the kidneys and vitamin C, including the role of vitamin C and its sources.

Grapefruit, which is high in vitamin C-2.Share on Pinterest
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A person’s body cannot make vitamin C, meaning they must consume it. The National Institutes of Health (NIH) recommend a daily intake of 75 milligrams (mg) for adult females and 90 mg per day for adult males.

They also state that the body does not store vitamin C. Instead, it uses the amount of vitamin C it needs and excretes the rest. When people eat 30–180 mg per day of vitamin C, their bodies absorb around 70–90% of it.

If a person eats 1 gram (g) of vitamin C per day, their bodies only absorb 50% of it. The kidneys filter the rest from the blood, and the body excretes it.


When the body breaks vitamin C down, it can convert into a compound known as oxalate. Typically, the kidneys filter oxalate, and the body excretes it through urine.

However, if a person with a kidney disorder consumes high levels of vitamin C, oxalate may start to build up inside their kidneys. This can lead to certain health issues, such as the formation of kidney stones.


A 2019 review notes that vitamin C may benefit people with certain types of kidney damage. Researchers state that it may be able to reduce certain symptoms of kidney damage, such as:

A doctor may recommend low dose vitamin C supplements for a person with kidney damage.

Kidney stones are hard masses that form in one or both of the kidneys if there are high levels of certain substances in the urine, such as calcium, uric acid, and oxalate.

Usually, the body excretes the chemicals that the kidneys filter from the blood through urination. However, if a person has higher amounts of certain chemicals and less liquid for it to dissolve into, crystals can begin to form inside the kidneys. These crystals may attract other chemicals, causing hard stones to develop.

Once a stone forms, it may pass into a person’s ureters. These two tubes allow urine to flow from the kidneys into the bladder. A person may pass tiny kidney stones without much pain. However, larger stones may become stuck inside the kidney or ureters. These stones can cause a person to experience severe pain.

According to the National Kidney Foundation, there are four types of kidney stones:

  • calcium oxalate
  • uric acid
  • cystine
  • struvite

Calcium oxalate stones are the most common form. High levels of vitamin C may increase the risk of calcium oxalate stones developing in people with kidney disorders.

A meta-analysis from 2022 suggests that an increased intake of vegetables and vitamin C may help reduce a person’s chances of developing renal cell carcinoma, a form of kidney cancer. However, researchers note that further evidence is necessary to confirm these findings.

A study from 2019 states that vitamin C may amplify the effects of chemotherapy. It may also reduce the side effects of this type of therapy.

However, the National Cancer Institute notes that people with a history of kidney disease should not receive IV vitamin C due to the risk of kidney failure. They also note that IV vitamin C is unsuitable for individuals prone to kidney stones. “IV” refers to fluids that a person receives into a vein.

Vitamin C is a nutrient that the body uses for various purposes, including:

  • acting as an antioxidant, meaning it helps prevent cell damage from free radicals
  • helping make collagen, an important protein for skin and connective tissue
  • helping wounds heal
  • improving the absorption of iron from plant-based foods
  • helping the immune system work properly

If a person does not have enough vitamin C in their diet, they may develop a vitamin C deficiency disease known as scurvy. This deficiency can cause a person to develop symptoms such as bleeding gums and fatigue.

A person typically consumes vitamin C from the food they eat.

Foods that are a good source of vitamin C include:

  • citrus fruits, such as oranges and grapefruits
  • tomatoes and tomato juice
  • potatoes
  • green and red bell peppers
  • kiwifruits
  • brussels sprouts
  • broccoli
  • strawberries
  • cantaloupe
  • fortified breakfast cereals
  • cabbage
  • cauliflower
  • green peas
  • spinach

A person may also consume vitamin C as a supplement or through multivitamins.

Vitamin C is a nutrient that plays a role in several important bodily processes. It is present in foods such as citrus fruits and certain vegetables. People with kidney problems may have to be careful with their vitamin C intake. Too much vitamin C may increase their chances of developing kidney stones.